Electronic displays are widely used. Although in the past the use of electronic displays has been primarily limited to computing applications such as desktop computers and notebook computers, as processing power has become more readily available, such capability has been integrated into a wide variety of applications. For example, it is now common to see electronic displays in applications such as smart phones, tablets, teller machines, gaming machines, automotive navigation systems, restaurant management systems, grocery store checkout lines, gas pumps, information kiosks, and hand-held data organizers to name a few.
Interactive visual displays often include some form of touch sensitive screen. Integrating touch sensitive panels with visual displays is becoming more common with the proliferation of portable multimedia devices, including smart phones and tablets. Capacitive touch sensing techniques for touch sensitive panels involve sensing a change in a signal due to capacitive coupling created by a touch on the touch panel. A voltage signal is applied to electrodes on the touch panel. A touch on the touch panel couples in a capacitance that alters the electric field in the vicinity of the touch. The change in the field is detected and used to determine the touch location.
Increasing the accuracy and/or decreasing the processing time of touch location determination is desirable. One previous patent that aids in fulfilling these needs is commonly owned and assigned U.S. Pat. No. 8,004,499 related to “Interleaved Electrodes for Touch Sensing.” Sensor designs in U.S. Pat. No. 8,004,499 offer increased accuracy and decreased processing time by providing sub electrodes that accompany primary electrodes of a touch sensing system, and interleaving the sub-electrodes of the system, enabling interpolation at the edges of the touch surface. The present description offers a further improvement to this technology, enabling higher resolution and simpler and less expensive fabrication while maintaining the same number of sensor channels.